NAO Index

NAO Index

24 November, 2023
Yoshihiro Tachibana (Mie University)

Return to Tachibna's home page (in Japanese)
Return to Tachibna's paper page

Graphics of daily time series of NAO index (click here)

Text file of the daily time series of NAO index (NCEP1) (JRA3Q)
Text file of the monthly time series of NAO index (NCEP1) (JRA3Q) (ERA5)

The definition of NAO index

1) EOF was applied to a temporal covariance matrix of geopotential height fields for individual calendar months using a monthly geopotential height field at 500 hPa for the north Atlantic region (50W-10E, 30-90N).
2) The daily time series of the NAO index is obtained by projecting daily geopotential height anomalies onto the EOF of each month.

Details are shown in Oshika et al. (2015) and Nakamura et al. (2015).

References

Oshika, M., Y. Tachibana and T. Nakamura (2015) Impact of the winter North Atlantic Oscillation (NAO) on the Western Pacific (NAO) pattern in the following winter through Arctic sea ice and ENSO: part I-observational evidence.Climate Dynamics, 45, 1355-1366. doi: 10.1007/s00382-014-2384-1. (Link)

Nakamura, T., M. Hara, M. Oshika and Y. Tachibana (2015) Impact of the winter North Atlantic Oscillation (NAO) on the Western Pacific (NAO) pattern in the following winter through Arctic sea ice and ENSO. Part II: multi-model evaluation of the NAO-ENSO linkage, Climate Dynamics, 45, 3547-3562. doi: 10.1007/s00382-015-2556-7. (Link)

Jones, P. D., T. Jonsson and D. Wheeler (1997) Extension to the North Atlantic Oscillation using early instrumental pressure observations from Gibraltar and south-west Iceland. International Journal of Climatology, 17, 1433-1450. doi:10.1002/(SICI)1097-0088(19971115)17:13<1433::AID-JOC203>3.0.CO;2-P. (Link)

ペット